Exhaust-fan



J. YOUNG.

EXHAUST FAN.

(No Model.)

No. 408,897 Patented Aug. 6, 1889.

UNITED STATES ATENT OFFICE.

JEFFERSON YOUNG, OF CHELSEA, MASSACHUSETTS.

EXHAUST-FAN.

SPECIFICATION forming part of Letters Patent No. 408,397, dated August6, 1889. Application filed March 2, 1889. Serial No. 301,757! (Nomodel.)

To all whom it may concern:

Be it known that I, JEFFERSON YOUNG, of Chelsea, in the county ofSuffolk and State of Massachusetts, have invented certain new and usefulImprovements in Exhaust-Fans, of which the following, taken inconnection with the accompanying drawings, is a specification.

My invention relates to exhaust-fans, and has for its objects theproduction of a fan that shall be more effective in its operation thanthose heretofore in use, and the blades of which may be readily adjustedto vary their pitch without increasing or diminishing the distance fromthe ends of said blades to the axis of the fan.

My invention consists in certain novel fea tures of construction,arrangement, and combination of parts, which will be readily understoodby reference to the description of the drawings, and to the claims to behereinafter given.

Figure 1 of the drawings is an elevation of an exhaustfan embodying myinvention. Fig. 2 is a vertical section on line a: 00 on Fig. 1. Fig. 3is a plan of the hub of the fan with all of the blades but one removed.Fig. 4 is an elevation of the central hub with one blade of the fan.Fig. 5 is a section through a portion of the central hub of thefan-wheel on line y g on Fig. 3 and illustrating the manner of securingthe blades in position in said hub. Figs. 6, 7, and 8 are transversesections of the fan-blade on lines 1 1, 2 2, and 3 3, respectively, onFig. l.

In the drawings, A A are two dastings composed of rim a, spokes b b, anda central hub c, the inner edges of said rims ahaving formed thereinannular grooves, in which are secured the edges of the sheet-metal hoopor band (I, which, with said rims a, comprise the peripheral casing forthe fan-wheel, the whole end areas inclosed by said casing, except whatis occupied by the spokes l) I), being left open.

B is the fan-shaft mounted in suitable bearings formed or secured in thehubs c c and projecting beyond one or the other of said hubs asuiiicient distance to receive a drivingpulley of any suitable size andstyle, but not shown in the drawings.

The shaft B maybe adjusted endwise in its bearings, was to project fromeither hub, according to the necessities of the place where it is to beused, and when properly adjusted it is prevented from moving endwise bythe collars e e, secured to the shaft by means of the set-screws e c, asshown in Fig. 2.

Upon the shaft B, between the hubs c c, is firmly secured so as torevolve therewith the hub O of the fan, which hub is composed of acylindrical center f and a series of radiating bosses g, in each ofwhich is formed a radial hole g and a transverse slot 9 extendingthrough said boss at right. angles to the hole 9, as shown invFigs. 4cand 5.

D D are the fan-blades, made, preferably, of sheet metal, and riveted tothe shanks D, which project beyond the inner or narrower ends of saidblades, and have formed upon said projecting portions malescrew-threads, and have fitted thereon the nuts h, as shown.

The shank D of each blade is fitted to one of the radial holes g, andhas fitted to its inner end the circular collar 1', which may bethreaded and screwed upon said shank or have a smooth fit thereon; butwhether the hole through it is smooth or threaded said collar, whenadjusted to the proper distance from the peripheral end of the blade D,is firmly secured to said shank, so as not to be revoluble thereon, by aset-screw or pin 1', as shown. By this method of securing the blades inthe hub C the angle or pitch of said blades may be readily increased ordiminished without changing the distance from the center of said simplyloosening the nuts h, turning said blades about the axes of theirshanks, and then screwing down said nuts h hard. upon the bosses g. Thisis a very valuable feature of my invention, for the reason that it isvery desirable to have the peripheral ends of the fan-blades revolve asclose to the inclosingcasing as practical without coming in contact withthe same; but when the shanks of the blades are screwed into the bossesof the hub, asheretofore practiced, if the blades revolve as closely asdesirable to the casing and it was desired to change the angles of theblade, it could not be done without lengthening or shortening thedistance from the center of the hub to the outer end of the blades withthe danger of greatly aifecting the oper hub to the peripheral end ofsaid blades by ICO ation of the fan by causing the ends of the blades tostrike the casing or removing them too far therefrom. The fan-bladesrevolve about the axis of the shaft B in the direction indicated by thearrows shown in connection with the several views of the drawings.

The several blades D D are set in the hub C, so that their ends areoblique to the axis about which they revolve, and are curved in thedirection of their widths with a varying degree and kind of curvature atdifferent distances from their inner ends, so that while the centers oftheir widths are straight radial lines their anterior and posterioredges are curved longitudinally or in the direction of their radiallengths, but with a different degree and kind of curve.

Each blade D is curved transversely 0n the line 2 2 of Fig. 4, or atabout one-third of the length of said blade from its inner end to an arcof a circle, as shown in Fig. 7, which curve may have a greater or lessradius, according to the requirements of the place where the fan is tobe used.

That portion of the blade which is outside of the line indicated above,instead of being curved throughout to an arc of a circle,has thatportion to the right of the center line 4 4 on Fig. 4 curved to aconstantly varying and increasing curve, as indicated in Figs. 3 and 6.

That portion of the blade outside of the line 2 2 and to the left ofline 4 4 and that portion inside of the line 2 2 and to the right ofline 4 4 (see Fig. 4) are curved to arcs of the same radius as the curveon line 2 2. The inner left-hand corner j of each blade is curved in theopposite direction, so that the inner end of the blade has across-section, as shown in Fig.8. By this form of blade at much moreeffective result is produced than can be produced by a fiat blade or ablade curved to arcs of uniform radii, as heretofore practiced.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is-

1. In an exhaust-fan, a blade havingits operating-face concavedtransversely and increasing in curvature from the center of its width toits posterior edge and from a point about one-third of its length fromits inner end to its outer posterior corner.

2. I11 an exhaust-fan, a blade having its operative face concavedtransversely and increasing in curvature from the center of its width toits posterior edge and from a point about one-third of its length fromits inner end to its outer posterior corner, and having its inneranterior corner curved in an opposite direction.

3. In an exhaust-fan, a series of screw blades concaved transversely andhaving a progressively-increasing pitch for about twothirds (more orless) of their lengths from their outer or peripheral ends inward, andhaving their inner anterior corners curved in the reverse directions.

4. In an exhaust-fan, the combination of the hub G g, provided with theradial holes g and the slots 9 the blade D, provided with a threadedshank, a collar firmly secured to the inner end of said shank within aslot 9 and a nut fitted upon said shank and arranged to bear upon saidhub G g to clamp said blade in position.

In testimony whereof I have signed my name to this specification, in thepresence of two subscribing witnesses, on this 28th day of February, A.D. 1889.

JEFFERSON YOUNG.

\Vitnesses:

N. 0. LOMBARD, WALTER E. LOMBARD.

